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Identification of genetic markers for lodging resistance in wheat - LK0958

Description

Identification of genetic markers for lodging resistance in wheat

Scope for continuing to reduce lodging risk by further shortening wheat crops will be limited because the more extreme dwarfing genes appear to be incompatible with high yields. Exploiting the wide genetic variation in stem and anchorage strength would significantly increase lodging resistance, but breeders have not improved these characters because they are very time-consuming to measure. Therefore selection for improved strength would be greatly assisted by the use of DNA markers; however, the genetic basis of these traits has never been investigated in elite UK winter wheat. Improving lodging resistance through stronger stems and anchorage would enable the greater yield potential of new varieties to realised, reduce reliance on plant growth regulators, reduce the likelihood of grain contamination by mycotoxins and allow the selection of taller varieties, which are better able to escape disease and out-compete weeds.

This project will test the following hypothesis: The underlying components of stem and anchorage strength are controlled by relatively few QTL, which function across environments and genetic backgrounds and have little or no pleiotropic effects on other agronomically important traits. A recently validated model of lodging has identified stem diameter, stem wall width, material strength of the stem wall and the spread and depth of the root plate as the underlying components of stem and anchorage strength. QTL for these traits will be mapped in two doubled haploid populations, derived from crosses involving elite UK winter wheat varieties, grown at two sites over three seasons. Pleiotropic effects on other agronomically important traits will be studied. A limited fingerprinting study will then survey a set of phenotyped varieties using the markers closely linked to QTL, controlling stem and anchorage strength, to study the occurrence of favourable alleles in a wider range of genetic backgrounds.
Objective
11 Objective(s)
Identify genetic markers that breeders can use to improve the lodging resistance of winter wheat.

This objective will be achieved by testing the following hypothesis:

The underlying components of stem and anchorage strength are controlled by relatively few QTL, which function across environments and genetic backgrounds and have little or no pleiotropic effects on other agronomically important traits.

11.1 Scientific objective(s)
Scientific Objectives (SOs) required to test the hypothesis include:
SO1 - Identify two doubled haploid populations whose parents vary for stem and anchorage strength.
SO2 - Measure the main plant characters underlying stem and anchorage strength in the two mapping populations, as well as other important agronomic traits.
SO3 – Construct linkage maps with a marker density of one microsatellite locus approximately every 20 to 30 cM in both DH populations.
SO4 - Identify QTL for stem and anchorage strength in both DH populations and compare the map locations with QTL identified in other cereal crop species.
SO5 - Compare and contrast the QTL effects across years, locations and populations and determine any negative pleiotropic effects on the other agronomic traits measured.
SO6 - Use the markers linked to the QTL to fingerprint phenotyped varieties for an association study in order to validate the utility of the SSRs across a wide range of genetic backgrounds.
11.2 Interdependence of objectives
SO2 and SO3 are dependent on SO1.
SO4 is dependent on SO2 and SO3.
SO5 is dependent on SO4.
SO6 is dependent of SO5.
11.3 Chances of achieving objectives
SO1 – almost 100% since some of the parents represent extreme stem and anchorage strength phenotypes (Spink et al., 2003) and another cross has wide segregation for lodging within lines of similar height (Appendix H).
SO2 and SO3 – almost 100% once SO1 has been achieved.
SO4 - there is a high chance of finding major QTL for many of the lodging associated characters, but it may not be possible to locate a major QTL for all of the traits measured.
SO5 – 100% if SO4 is achieved, but it is not known how many QTL will be population specific.
SO6 – 100% if SO5 is achieved.
11.4 Factors, specific to the project, which might delay achieving the objective(s)
None
Time-Scale and Cost
From: 2004

To: 2008

Cost: £342,027
Contractor / Funded Organisations
Advanta, ADAS UK Ltd., Home Grown Cereals Authority
Keywords
Agricultural Land              
Arable Farming              
Crop Improvement              
Farming              
LINK Programme              
Resistance              
Sustainable Farming and Food              
Technology Transfer              
Wheat              
Wheat Production              
Fields of Study
Arable Crops